Revert "GA for gVNIC support (#4511)"

[c2thorn]

This reverts commit d63a4a8.

#4511 works fine for Compute Instances, but there is issues with Instance Templates. Reverting for now.

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Ran relevant acceptance tests (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

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[c2thorn]

Closing, I see #4516 is pending

[c2thorn]

/gcbrun

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 4 files changed, 1 insertion(+), 101 deletions(-))
Terraform Beta: Diff ( 3 files changed, 1 insertion(+), 3 deletions(-))
TF Conversion: Diff ( 1 file changed, 9 deletions(-))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=173789"

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 4 files changed, 1 insertion(+), 101 deletions(-))
Terraform Beta: Diff ( 3 files changed, 1 insertion(+), 3 deletions(-))
TF Conversion: Diff ( 1 file changed, 9 deletions(-))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=173790"

[edwardmedia]

LGTM. Thanks